Maintenance of the Brugia malayi life cycle in Mongolian gerbils

The Mongolian gerbil or jird (Meriones unguiculatus) is a rodent belonging to the subfamily Gerbillinae. They are commonly used as models for a variety of infectious diseases such as Hepatitis E virus and Giardia lamblia. At the LSTM/University of Liverpool (UoL) these gerbils (Figure 3) are infected with Brugia malayi, a laboratory strain of a human parasitic nematode, that causes Lymphatic Filariasis (LF) (Figure 1). To maintain this lifecycle (Figure 2) we need to harvest juvenile larval stages known as microfilaria by abdominal lavage. Previously microfilaria were harvested from the peritoneal cavity by using a needle and syringe on anaesthetised gerbils held vertically. This method often resulted in low yields of parasites due to the low volume of media recovered and carried the risk of damaging the abdominal organs. A refinement of this technique is to use a gravity assisted method (Figure 4) with a 20G catheter and a 5ml syringe to inject and aspirate warm sterile RPMI media, containing 1% Penicillin/Streptomycin and Amphotericin B. This refinement allows the gerbil to lay horizontally during lavage, which reduces the risk of damage to internal organs. This improves the welfare of the gerbil and results in an increased number of microfilaria (Figure 5) which typically can yield between 400,000 to more than 1,000,000 mf/ml.